Carbonate compounds are currently used as electrolyte solvents for non-aqueous batteries containing cathodes made from alkali metals, alkaline earth metals, or compounds comprising these metals, for example lithium ion batteries. Current lithium ion battery electrolyte solvents typically contain one or more linear carbonates, such as ethyl methyl carbonate, dimethyl carbonate, or diethylcarbonate; and a cyclic carbonate, such as ethylene carbonate. However, at battery voltages above 4.4 V these electrolyte solvents decompose resulting in a loss of battery performance. Additionally, there are safety concerns with the use of these electrolyte solvents because of their low boiling point and high flammability.
To overcome the limitations of commonly used non-aqueous electrolyte solvents, several new carbonate compounds have been developed. For example, Yokoyama et al., (U.S. Pat. No. 5,659,062) describe novel carbonate compounds given by the general formula R1CH2O—CO—OCH2R2, wherein R1 represents a hydrogen atom, an alkyl group, or an alkyl group substituted with one or more halogen atoms, and R2 represents an alkyl group having no hydrogen atom at the α-position thereof or an alkyl group substituted with one or more halogen atoms and having no hydrogen atom at the α-position thereof, with the proviso that R1 is not identical to R2. Additionally, various fluorinated ester electrolyte solvents have been described for use in lithium ion batteries (see for example, Nakamura et al. JP4328915B2).
Xu et al. (J. Electrochem. Soc. 149(7):A920-A926, 2002) have proposed the use of sulfone-based electrolytes, including fluorinated sulfones such as 3,3,3,-trifluoropropylmethyl sulfone, for lithium ion batteries.
However, the need exists for more electrolyte solvents, which are highly stable to oxidation and have a high boiling point, for use in non-aqueous battery systems, such as lithium ion batteries.